But as it stands would severely reduce Llandudno's service. Even if replaced by a Liverpool service it'd still be a reduction (and removal of a long established through service)
My understanding is that there'd be the same hourly service from Llandudno to Chester, but going to Liverpool rather than Manchester. There will also be ample turnaround time for the hourly shuttle to Llandudno Jn too, as the paths to and from Liverpool indicate trains will pass each other at Chester just like the current Manchester service does.
I've had a quick dig in the train service requirements for December
2019 and
2022 (when the new timetable is to start), and found that the minimum number of through services Chester-Llandudno is due to increase from 12 to 17. Counting all services between the Junction and Llandudno, the specification increases from 27 to 32.
The only loss I can find is the fact that there won't be direct trains to Warrington, Earlestown and Manchester from Llandudno and Deganwy (only from Llandudno Jn).